1. Field of the Invention
The field of the invention includes embodiments that relate to media transmission systems and methods, and more particularly to a system and method for adaptively controlling bit rates of media streams transmitted across an IP network.
2. Discussion of Related Art
Media streaming is used to transmit media from senders to receivers through an IP network. The IP network may include Internet, Intranet, or a local area network. The media refers to video, audio, or other multimedia data. For video streaming applications, as an example, it is desirable to stream videos over the IP network in a reliable and cost effective manner. However video streaming, particularly live video streaming, usually demands certain amount of bandwidth, it imposes challenges to resource restricted network. When the network is congested and no adequate bandwidth is reserved for video streaming, the packets will be inevitably dropped during transmission, thus make it difficult or impossible for the video receiver to reconstruct video due to packet losses.
For example, in a video surveillance system, devices, such as IP cameras, are installed to capture video of different scenes. The video stream data is encoded, and then transmitted across IP network to a video decoder. Each video stream consumes certain amount of bandwidth of the IP network. Since video streams may need to be route through network bottlenecks, where limited bandwidth is shared between dynamic traffic flows available bandwidth for video streaming can not always be guaranteed, which poses challenges to guarantee the quality of the video received by the receiver. Therefore, it is desirable to have a system and a method to dynamically adjust video streaming rate according to the available bandwidth. In this way, network congestion is relieved by sending less video data, video quality is improved due to less packet drops. Meanwhile, once the congestion is relieved and more bandwidth is available, we increase the streaming rate to take advantage of it. The collaborative, adaptive video streaming framework enables more intelligent use of the IP network bandwidth and delivers better video quality to the end users.